Derivatives of trimellitic acid anhydrides



United States Patent "ice 3,140,299

Patented July 7, 1964 1 p 2 acidolysis reaction is unique in the sense that the reaction 3,140,299 takes place on the No. 4 carboxylic acid position, thus,

DERIVATIVES OF TRIME'IJLITIC ACID ANHYDRIDES leaving the 1,2 positions intact. For example, in the Donald F. Loncfini Schenectady NY assignor to care of trimellitic anhydride, only the free carboxylic General Electric colilpany, a corpmfion 3 New York 5 acid group reacts leaving intact the anhydride linkage.

N0 Drawing Filed AP 1962, Sen. 190,803 If trimellitic acid is used, then the 1,2-dicarboxylic acid 4 Cl i (C1, 2 0 346 3 groups form the anhydride by splitting out one molecule of Water before the transesterification reaction proceeds.

This invention relates to new and useful compositions. In either case, the reaction products are the same. Among More particularly, it relates to new anhydride materials 10 the other tribasic materials which can be used besides and to epoxy resins cured with such anhydrides. trimellitic anhydride or its acid are 1,2,4 naphthalene The use of anhydride materials for curing epoxy resins tricarboxylic acid, 1,4,8 napthalene tricarboxylic acid, is well known. However, with the development of elec- 1,2,4 butane tricarboxylic acid, 1,2,3 benzene tricartrical and other equipment which operates at elevated boxylic acid, 1,2,3 propane tricarboxylic acid and 2,3- temperatures and under great physical stress, there has 6-napthalene tricarboxylic acids or their corresponding come about a corresponding requirement for new epoxy anhydrides, among others. In preparing the anhydrides, resin compositions which would be able to meet such equimolar parts of an ester or amide are reacted with requirements. It is a primary object, therefore, of this one part of trimellitic anhydride, for example, or other invention to provide new cured epoxy resin compositions tribasic material as described above either in the presence which will be capable of operating at high temperatures. or absence of solvents and with or without catalysts of It is a further object of this invention to provide curing the transesterification type. Among the solvents which agents which make practicable such cured epoxy resin are useful in connection with the present invention are compositions. the chlorinated aromatic materials. Among the trans Briefly, the invention relates to novel monoanhydrides esterification catalysts which are well known to those derived from anhydrides of tricarboxylic acids and to skilled in the art are MgO, Mg, Li CO H 50 HgSO epoxy resins cured with such materials. etc. Generally, reaction takes place in a temperature Those features of the invention which are believed to range of from about 125 C. to 300 C. and is complete be novel are set forth with particularity in the claims apwhen the theoretical amount of lower boiling acid has been pended hereto. The invention will, however, be better removed by distillation. Normally, this takes place beunderstood from a consideration of the following descriptween 30 and 100 minutes. In general, any ester acid tion. derivative of the hydroxy, amino or mercapto compound The novel anhydride materials of the present invention can be used such as formate, acetate, propionate, and correspond to the following general formula the like. However, from the point of view of convenience and preparation and cheapness of raw materials, the acetates are generally preferred, except, of course, when the corresponding ester, amide or thioester is of such low boiling point that no reaction takes place. In such case, other higher boiling point derivatives are employed.

Any 1,2 epoxy resins containing an average of more than one epoxy group per resin molecule may be used, such epoxy resins derived from various source materials being well known in the art. Epoxy resins are described, for example, in U. S. Patent 2,324,483 relating to epoxy resins which are the reaction product of a phenol containing two phenolic hydroxy groups and an epihalohydric, such as epichlorohydrin, in which the product contains at and Y can be substituted or unsubstituted aromatic, least two P Y p yp Phenols which are P alicyclic, aliphatic or heterocyclic groups, include 2,2-b1s-(4-hydroxyphenyl) propane resorcinol,

For example, Y can vbe an aromatic group Such as 50 2,2-b1s-(4-hydroxyphenyl) butane and others. Furtner pheny, ethyl phenyl, naphthyl nonyl phenyl or nitro examples of epoxy resins are disclosed in U. S. Patents or halo substituted aromatic group. It can also be ali- 2149412951 2500;600 and 2,511,913- These epoxy T351115 phatic, for example stearyl, lauryl, nonyl, etc. Among are generally known as y y P Y resins and atypical the useful groups are cyclohexyl, cyclobutyl, cyclopentyl reaction for preparing such an epoxy resin from the reand derivatives thereof. Others will occur to those skilled action of epichlorohydrin with 2,2-bis-(4-hydroxyphenyl)- in the art. propane is shown below:

CH 1 Alkali HO C OH (ll-OH -CH-CHg 6 H3 0 lon, -I on cur-oH-oH2-0C -o-omon-oH2oC cC -o-omonorn l Ha $11 In 5H; 0

Generally speaking, the anhydrides of the present in- Where It has an average value varying from around vention can be readily prepared in quantitative yields by zero to about 9. Many of these ethoxyline resins are an acidolysis reaction between equimolar amounts of trisold under the name of Epon resins by Shell Chemical carboxy acid or anhydride and an ester, or amide. This I Corporation, or Araldite resins by the Ciba Company.

G Data on several of the Epon resins found suitable for the instant purpose are given in the table below:

Epoxy Resin Epoxide M.P., C.

Equivalent Epon 562 140-165 Liquid. Epon 820 192 D0. Epon 826 175-190 Do. Epon 828 192 9. Epon 834. 225-290 20-23. Epon 1004 300-375 40-45. Araldlte 60l0 192 Liquid Aralditc 6020 200-205 Do. ERL 2774 175-200 D0. Epi-Rez 510 175-200 D0. Bakelite 2774 100-196 DO.

Example 1 A mixture of 96 grams (0.5 mole) of trimellitic anhydride, together with 103 grams (0.5 mole) of p-phenylphenyl acetate and 100' cc. of Aroclor No. 1242, a chlorinated polyphenyl material, was stirred and heated to a maximum temperature of 310 C. over a two-hour period. A total of 29 grams of acetic acid was collected and the mixture allowed to cool to 80 C. The product was precipitated with 200 cc. of n-hexane, filtered, washed three times with boiling n-hexane and dried. There was obtained a yield of 163 grams of product corresponding to 97% of theory and having a melting point of 221 to 222 C. and a neutral equivalent of 174. This material can be characterized as 4-p-phenylphenyl trimellitate anhydride.

Example 2 A mixture of 96 grams (0.5 mole) of trimellitic anhydride, 67.5 grams (0.5 mole) of acetanilide and 300 cc. of diphenyl ether was stirred and heated to a maximum temperature of 260 C. over a two-hour period. A total of 29.7 grams of acetic acid was distilled over corresponding to a yield of 99% of the theoretical. After cooling to 100 C., the product was filtered, washed three times in boiling n-hexane and dried to give a total of 136 grams or a 90% yield having a melting point of 225 C. to 226 C. and a neutral equivalent of 129. This material is 4-phenyl trimellitamide anhydride.

Example 3 There were mixed together 192 grams (1.0 mole) of trimellitic anhydride and 270 grams (1.01 moles) of nonylphenyl acetate, which was prepared by the acetylation of nonylphenol wtih acetic anhydride, the mixture being heated to a top temperature of 290 C. over a twohour period. Sixty grams of acetic acid distilled over and the mixture cooled to a viscous mass. A portion of the viscous mass was crystallized in n-hexane as above to a fine powder melting at 154 C. to 156 C. and having a neutral equivalent of 195. This material is 4-nonylphenyl trimellitate anhydride.

Example 4 A mixture of 57.6 grams (0.3 mole) of trimellitic anhydride and 93.3 grams (0.3 mole) of stearylacetamide was stirred and heated over a 15-minute period to a maximum temperature of 180 C., during which time there were collected 18 grams of acetic acid. This mixture was cooled to 80 C. and 400 cc. of n-heptane added and the product filtered. After recrystallizing in n-heptane, there were obtained grams or a 99% yield of waxy 4-stearyl trimellitamide anhydride having a melting point of 126 C. and a neutral equivalent of 222.

Example 5 There were reacted together over a one-hour period, to a maximum temperature of 310 C., 96 grams (0.5 mole) of trimellitic anhydride with 156 grams (0.5 mole) of stearyl acetate. There were also obtained, by precipitating in n-hexane and recrystallizing as in Example 1, 210 grams or a 95% yield of 4-stearyl trimellitate anhydride melting at 98 C. and having a neutral equivalent of 221.

Example 6 The procedure of Example 4 was repeated using 76.8 grams (0.4 mole) of trimellitic anhydride with 90 grams (0.4 mole) of laurylacetamide. The product obtained weighed grams for 98% yield of 4-lauryl trimellitamide anhydride which melted at 135 C. and had a neutral equivalent of 186.

Example 7 There were mixed together 21.3 grams of finely pulverized 4-p-phenylphenyl trimellitate anhydride of Example l with 15 grams of Epon 562. The mixture was placed in an aluminum dish in a 125 C. air-draft oven. The mixture gelled after about 15 minutes and was fully cured after two hours to a hard, rigid mass. Aging for four hours at C. produced no changes in property nor did aging for two hours at 210 C. The cured resin was found to be strongly anchored to the aluminum metal of the dish.

Example 8 The powdered 4-phenyl-trimellitamide anhydride of Example 2 was mixed with Epon 562 in the proportion of 0.8 mole of anhydride per epoxy equivalent. The mixture cured to a tough, rigid, infusible mass at 125 C. in about two hours.

Example 9 The 4-nonylphenyl trimellitate anhydride of Example 3 was mixed with Epon 562 in the proportion of 0.6 mole of anhydride per epoxy equivalent. The material cured to a tough, flexible, infusible mass at 125 C. in about two hours. The cured epoxy resin was found to be tough and flexible at room temperature as well and was characterized by good adhesion to aluminum.

Example 10 The 4-nonylphenyl trimellitate anhydride of Example 3, which had been crystallized in n-hexane, was combined with Epon 826 in the proportion of 0.6 mole of anhydride per epoxy equivalent and cured for two hours at 125 C. to obtain a tough, flexible material. This material, at a temperature of C., was extremely pliable but still retained its toughness.

Example 11 The 4-stearyl trimellitamide anhydride of Example 4 was mixed with Epon 562 in the amount of 0.8 mole of anhydride per epoxy equivalent. This material, when cured for four hours at 125 C., produced a tough, flexible cast material.

Example 12 The 4-stearyl trimellitate anhydride, when mixed with Epon 562 in an amount of 0.8 mole of anhydride per epoxy equivalent and cured for two hours at 125 C., produced a tough, flexible material.

Example 13 The 4-lauryl trimellitarnide anhydride of Example 6, when mixed with Epon 562 in the amount of 0.8 mole 3. 4-pheny1 trimellitamide anhydride. 4. 4-nonylpheny1 trimellitate anhydride.

References Cited in the file of this patent UNITED STATES PATENTS Bradley Mar. 14, 1950 Shokal et al. Dec. 24, 1957 Delmonte June 9, 1959 Knobloch et a1 Nov. 3, 1959 Merrill et al. Sept. 26, 1961 Bennett et al. Feb. 20, 1962 McKinnis et al. Mar. 27, 1962 Stephens et al Nov. 13, 1962 

1. AN ANHYDRIDE CHOSEN FROM THE GROUP CONSISTING OF 4-P-PHENYLPHENYL TRIMELLITATE ANHYDRIDE, 4 - PHENYL TRIMELLITAMIDE ANHYDRIDE AND 4-NONYLPHENYL TRIMELLITATE ANHYDRIDE. 